1. Field of the Disclosure
The present disclosure relates generally to an electrostatographic printing apparatus, and more particularly, concerns a system and method for charging and erasing the surface of a photoreceptor in such a machine.
2. Description of Related Art
Typically, in an electrostatographic printing process of printers, a photoconductive or photoreceptor member is charged by a charging device to a substantially uniform potential so as to sensitize the surface thereof. The charged portion of the photoreceptor member is exposed to selectively dissipate the charges thereon in the irradiated areas. This records an electrostatic latent image on the photoreceptor member. After the electrostatic latent image is recorded on the photoreceptor member, the latent image is developed by bringing a developer material into contact therewith. Generally, the developer material comprises toner particles adhering triboelectrically to carrier granules. The toner particles are attracted from the carrier granules either to a donor roll or to a latent image on the photoreceptor member. The toner attracted to the donor roll is then deposited on latent electrostatic images on a charge retentive surface, which is usually a photoreceptor. The toner powder image is then transferred from the photoreceptor member to a copy substrate.
In order to fix or fuse the toner material onto a support member permanently by heat, it is necessary to elevate the temperature of the toner material to a point at which constituents of the toner material coalesce and become tacky. This action causes the toner to flow, to some extent, onto fibers or pores of the support members or otherwise upon surfaces thereof. Thereafter, as the toner materials cool, solidification of the toner materials occurs causing the toner material to be bonded firmly to the support member.
Transfer is typically carried out by the creation of a “transfer-detack zone” (often abbreviated to just “transfer zone”) of AC and DC biases where the print sheet is in contact with, or otherwise proximate to, the photoreceptor member. A DC bias applied to the back (i.e., on the face away from the photoreceptor member) of the paper or other substrate in the transfer zone electrostatically transfers the toner from the photoreceptor member to the paper or other substrate presented to the transfer zone. The toner particles are heated to permanently affix the powder image to the copy substrate. Biased transfer rolls are also used to transfer an image from a photoreceptor member to media, for example, the segmented bias roll disclosed in U.S. Pat. No. 3,847,478.
An erase device is used to remove any remaining photoreceptor charge in the xerographic process, such as, shown in U.S. Pat. Nos. 4,534,641 and 7,424,250 B2. Known charge/discharge systems utilize different charging devices such as a pin scorotron or dicorotron, and different erase mechanisms such as erase lamps or wires and different AC and DC power supplies. The different components and power supplies required for the charging and erase functions can be quite costly.
Thus, there is still a need for a system and method for performing the charge/erase functions at reduced cost.